Bf109F vs P-38F

[Juha]

I did some checking on those projects that didn't produce service fighters. Many of the abandoned projects were attempts by Curtiss to produce a new fighter to USAAC/USAAF. XP-42, -46, -53/60 (up to E version), -62; then there were those unconventional planes XP-54, -55, -56, -67. One cannot accuse USAAC/USAAF being too conservative. US must to have used a lot of R&D resources to all those projects, but fortunately it was a rich country with powerful industrial base. Then there was lightweight XP-77 and the "choose your parts and put them together" P-75, even if the idea didn't come true in the end product. Of course there were others, for ex Lockheed's XP-49 and -58.
Purely export projects were P-64, -66 and CW-21

 

[drgondog]

I did some checking on those projects that didn't produce service fighters. Many of the abandoned projects were attempts by Curtiss to produce a new fighter to USAAC/USAAF. XP-42, -46, -53/60 (up to E version), -62; then there were those unconventional planes XP-54, -55, -56, -67. One cannot accuse USAAC/USAAF being too conservative. US must to have used a lot of R&D resources to all those projects, but fortunately it was a rich country with powerful industrial base. Then there was lightweight XP-77 and the "choose your parts and put them together" P-75, even if the idea didn't come true in the end product. Of course there were others, for ex Lockheed's XP-49 and -58.
Purely export projects were P-64, -66 and CW-21

All true Juha. On the USN side I would offer a couple that tend to fit long gestation period even if not with quite so many production release versions beforehand - the F4U and SB2C took 2.5 and 3 years respectively from first flight before deemed combat ready. The P-47C was fighting with 56th/78th and 4th FG in two years from first flight.

Part of the problem with the P-38 and the P-39 is that the combat role and mission envisioned was not what they confronted and no ready replacements for the new role was available. The US "brought what they had" and modified for a period of time to meet a broader range of needs.

Germany had a clear vision regarding the type of war they were going to fight, as well as the tactical doctrine so I think they did a better job in 1938 and 1939 setting specifications.

Both the P-47 and P-38s were designed as bomber interceptors - never as strategic escorts/air superiority fighters - but they evolved.

Had the Merlin engine been available to US in 1939 as a foundation for in-line high altitude/high performance aircraft it would have been interesting to see how the US designs would have looked like in 1941. The Mustang would have been air superiority combat ready in 1942, US airpower would have been effective in early 1943 and the LW would have been forced to respond to the threat by accelerating the Fw 190D/Ta 152 and the Me 262.

While the P-51B would have been superior to the P-38E through J and all versions of P-40 and P-39, I doubt that the impact would have been as great in PTO for all USAAF initiatives... and the USN would have had the same types no matter what.

The one intersting question would have been the USMC if the 51B available in flight test during 1941 and combat ops by Pearl Harbor when the F4U was still a year away from serious consideration in the Solomons... No question that the 51 would have been far more effective on Japanese bombers (given radar) a long way out from Guadalcanal compared to F4F and P-40 and P-39.

As to the eternal performance debates I am in agreement with you. The preliminary design phase of aircraft is loaded with a range of mathmatically derived (and simplified) relationships for Lift and Drag. Attempts have to be made to reduce conceptual wing body designs to project performance.

The equations often presented here are correct for such studies - but only relate to stable bodies in linear motion, immersed in a perfect fluid, in linear regions.

The Dynamic 'Turn' model is an approach to extend the above principles and assumes symmetric forces on a curvelinear wing/body path... and assumes that at each point in the turn that the Free Body Force diagram applies equally to a banked wing/body system that is in fact experiencing asymmetric forces and spanwise flow across most or all surfaces with significant changes to lift and drag - and does not take into account turbulent flow, boundary layer separation, elastic properties of the airframe, etc.

Reality sets in during flight tests....

 

[renrich]

A German pilot called the P38 vulnerable. If one looks at combat film from the LW showing an attack on a P38, one can see that the same thing that made it easy to see and identify made it vulnerable. It was a big AC and there was a lot of vulnerable spots to shoot at. Throw some lead it it's general direction and it is much more likely to hit something on a P38 than on a single engined fighter.